U.S. patent application number 10/643388 was filed with the patent office on 2005-02-24 for automatic defrost controller including air damper control.
This patent application is currently assigned to Electrolux Home Products, Inc.. Invention is credited to Cushman, Robert L., Ruedger, Stephen.
Application Number | 20050039472 10/643388 |
Document ID | / |
Family ID | 34193861 |
Filed Date | 2005-02-24 |
United States Patent
Application |
20050039472 |
Kind Code |
A1 |
Cushman, Robert L. ; et
al. |
February 24, 2005 |
Automatic defrost controller including air damper control
Abstract
A damper apparatus for controlling airflow between compartments
in a two compartment refrigerator having a door includes a
controller for controlling opening and closing of a damper; and a
door sensor connected to the controller for detecting when the door
is open. If the controller determines that the door has remained
closed for a set period, the controller maintains the damper in the
closed position. A method for cleaning a damper in a refrigerator
includes a steps of defrosting a refrigeration apparatus of the
refrigerator, at least partially opening the damper, followed by
waiting for a set period and then at least partially closing the
damper. The steps of at least partially opening and waiting are
repeated a set number of times and then a cooling operation of the
refrigeration apparatus is commenced.
Inventors: |
Cushman, Robert L.; (Sparta,
MI) ; Ruedger, Stephen; (Grand Rapids, MI) |
Correspondence
Address: |
PEARNE & GORDON LLP
1801 EAST 9TH STREET
SUITE 1200
CLEVELAND
OH
44114-3108
US
|
Assignee: |
Electrolux Home Products,
Inc.
Cleveland
OH
|
Family ID: |
34193861 |
Appl. No.: |
10/643388 |
Filed: |
August 19, 2003 |
Current U.S.
Class: |
62/187 ;
62/408 |
Current CPC
Class: |
F25B 2600/112 20130101;
Y10T 137/86734 20150401; F25D 2700/02 20130101; F25D 2700/12
20130101; F25D 2400/06 20130101; F25D 17/045 20130101; F25D 21/08
20130101; F25D 2700/122 20130101 |
Class at
Publication: |
062/187 ;
062/408 |
International
Class: |
F25D 017/04 |
Claims
1. A refrigerator comprising: a cabinet; a first refrigerated
compartment within the cabinet having a door; a second refrigerated
compartment within the cabinet; a dividing wall separating the
first refrigerated compartment from the second refrigerated
compartment; a duct connecting the first refrigerated compartment
for airflow communication with the second refrigerated compartment;
a damper movable between an open position and a closed position for
controlling airflow within the duct; a refrigeration apparatus
having a refrigeration cycle being measured from a first starting
of the refrigeration apparatus to a second consecutive starting of
the refrigeration apparatus, and an off cycle being a time within
said refrigeration cycle during which the refrigeration apparatus
is not operating; a controller for controlling the damper; and a
door sensor connected to the controller for detecting when the door
is open; wherein if the controller determines that the door has
remained closed for a set number of refrigeration cycles, the
controller maintains the damper in the closed position during a
subsequent consecutive off cycle.
2. The refrigerator of claim 1, wherein the refrigeration apparatus
is a compressor.
3. The refrigerator of claim 1, wherein the set number of
refrigeration cycles is three.
4. The refrigerator of claim 1, wherein the set number of
refrigeration cycles is one.
5. An apparatus for controlling airflow between compartments in a
two compartment refrigerator having a door, the apparatus
comprising: a damper for opening and closing a duct between the two
compartments of the refrigerator; a controller for controlling the
opening and closing of the damper; and a door sensor connected to
the controller for detecting when the door is open; wherein if the
controller determines that the door has remained closed for a set
period, the controller closes and/or maintains the damper in the
closed position during a subsequent operation of a refrigeration
apparatus.
6. The apparatus of claim 5, wherein the two compartments comprise
a frozen food compartment and a fresh food compartment, the door
being associated with the fresh food compartment.
7. The apparatus of claim 5, wherein the door sensor is a
switch.
8. The apparatus of claim 5, wherein the set period is a set number
of on/off cycles of a compressor of the refrigerator.
9. The apparatus of claim 8, wherein the set number of on/off
cycles is three.
10. A self defrosting refrigerator comprising: a cabinet; a first
refrigerated compartment within the cabinet having a first door; a
second refrigerated compartment within the cabinet having a second
door; a dividing wall separating the first refrigerated compartment
from the second refrigerated compartment; a duct connecting the
first refrigerated compartment for airflow communication with the
second refrigerated compartment; a damper movable between an open
position and a closed position for controlling airflow within the
duct; a refrigeration apparatus within the cabinet; and a
controller for controlling the damper; wherein the controller
carries out a damper cleaning operation in which the controller at
least partially opens and then at least partially closes the damper
a set number of times at a set interval.
11. The refrigerator of claim 10 wherein the controller carries out
the damper cleaning operation prior to energizing an evaporator
fan.
12. The refrigerator of claim 10, further comprising a defrosting
apparatus, wherein the controller carries out the damper cleaning
operation subsequent to an operation of the defrosting
apparatus.
13. The refrigerator of claim 10, further comprising a defrosting
apparatus, wherein the controller carries out the damper cleaning
operation between an operation of the defrosting apparatus and a
subsequent consecutive energizing of the evaporator fan.
14. The refrigerator of claim 10, wherein during the cleaning
operation the damper is moved from a fully open position to a fully
closed position.
15. A damper cleaning apparatus for a two compartment refrigerator
having a damper for controlling airflow between compartments, the
damper cleaning apparatus comprising: a damper drive mechanism for
opening and closing the damper; and a controller for controlling
the damper drive mechanism wherein the controller caries out a
cleaning operation by at least partially opening and then partially
closing the damper a set number of times at a set interval.
16. The damper cleaning apparatus of claim 15, wherein the
controller carries out the damper cleaning operation prior to an
operation of the an evaporator fan of the refrigerator.
17. The damper cleaning apparatus of claim 15, wherein the
controller carries our the damper cleaning operation subsequent to
a defrost operation of the refrigerator.
18. A method for cleaning a damper in a refrigerator comprising
steps of: at least partially opening the damper; following the step
of opening, waiting for a set period and then at least partially
closing the damper; and repeating the steps of at least partially
opening and waiting a set number of times.
19. The method of claim 18, further comprising a step of initiating
a defrosting operation of the refrigerator prior to the step of
opening.
20. The method of claim 18, further comprising a step of commencing
a cooling operation of the refrigeration apparatus following the
step of repeating.
21. The refrigerator of claim 1, wherein the controller opens the
damper during an off cycle when the second refrigerated compartment
requires cooling.
22. A refrigerator comprising: a cabinet; a first refrigerated
compartment within the cabinet having a door; a second refrigerated
compartment within the cabinet; a dividing wall separating the
first refrigerated compartment from the second refrigerated
compartment; a duct connecting the first refrigerated compartment
for airflow communication with the second refrigerated compartment;
a damper movable between an open position and a closed position for
controlling airflow within the duct; a refrigeration apparatus
having a refrigeration cycle being measured from a first starting
of the refrigeration apparatus to a second consecutive starting of
the refrigeration apparatus, and an off cycle being a time within
said refrigeration cycle during which the refrigeration apparatus
is not operating; a controller for controlling the damper; and a
door sensor connected to the controller for detecting when the door
is open; wherein if the controller determines that the door been
opened during a set number of prior refrigeration cycles, the
controller opens the damper when the second refrigerated
compartment requires cooling.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to automatic defrost controls
for two compartment refrigerators, and more particularly to
automatic defrost controllers including air damper control.
[0002] Refrigerators having two refrigeration compartments,
including a fresh food compartment and a frozen food compartment,
are well known. Many of these two compartment refrigerators have
refrigeration apparatus connected to the frozen food compartment
and a duct for carrying cool air from the frozen food compartment
to the fresh food compartment. In order to regulate the temperature
of the fresh food compartment, a damper or baffle is often provided
within or adjacent to the duct. The baffle is thermostatically
controlled to provide a desired temperature within the fresh food
compartment.
[0003] Self defrosting refrigerators generally include a defrost
heater for melting ice that has accumulated on the refrigeration
apparatus. However, the operation of the defrost heater will often
cause water to accumulate on or near the air duct damper.
Subsequently, especially when the cooling apparatus is operated,
the water can freeze and form ice that interferes with the
effective operation of the damper.
[0004] In order to avoid this problem, a number of solution has
been proposed. In U.S. Pat. No. 5,201,888 to Beach et al. a control
moves the damper to a fully closed position while energizing the
defrost heater. Thus, the formation of condensation and subsequent
ice formation is reduced. However, water can still accumulate on
the baffle, which later freezes, especially when the defrost heater
must be operated for an extended period of time.
[0005] U.S. Pat. No. 5,375,413 to Fredell et al. discloses a
two-element sliding air baffle for a refrigerator. The second
baffle element is operated by a solenoid that, in a closed
position, is periodically pulsed (every one minute) thereby
exerting a repeated rocking or leveraging motion on the second
baffle member. The rocking motion enhances the break up of any ice
that has formed between the two baffle elements. However, once ice
has formed, it can be very difficult to remove.
[0006] Further, energy conservation is becoming more and more
important in appliances such as refrigerators. Although many energy
saving measures have been developed, there are significant
inefficiencies in the operation of such refrigerators.
[0007] Thus, there is a need for a refrigerator capable of
preventing the build-up of ice on an air duct damper. Further,
there is a need for improving the energy efficiency of
refrigerators.
SUMMARY OF THE INVENTION
[0008] According to a first aspect, the present invention provides
a refrigerator comprising a cabinet; a first refrigerated
compartment within the cabinet having a door; a second refrigerated
compartment within the cabinet; a dividing wall separating the
first refrigerated compartment from the second refrigerated
compartment; a duct connecting the first refrigerated compartment
for airflow communication with the second refrigerated compartment;
a damper movable between an open position and a closed position for
controlling airflow within the duct; a refrigeration apparatus
having a refrigeration cycle being measured from a first starting
of the refrigeration apparatus to a second consecutive starting of
the refrigeration apparatus, and an off cycle being a time within
said refrigeration cycle during which the refrigeration apparatus
is not operating; a controller for controlling the damper; and a
door sensor connected to the controller for detecting when the door
is open. If the controller determines that the door has remained
closed for a set number of refrigeration cycles, the controller
maintains the damper in the closed position during a subsequent
consecutive off cycle.
[0009] According to a second aspect, the present invention provides
a self defrosting refrigerator comprising: a cabinet; a first
refrigerated compartment within the cabinet having a first door; a
second refrigerated compartment within the cabinet having a second
door; a dividing wall separating the first refrigerated compartment
from the second refrigerated compartment; a duct connecting the
first refrigerated compartment for airflow communication with the
second refrigerated compartment; a damper movable between an open
position and a closed position for controlling airflow within the
duct; a refrigeration apparatus within the cabinet; and a
controller for controlling the damper. The controller carries out a
damper cleaning operation in which the controller at least
partially opens and then at least partially closes the damper a set
number of times at a set interval.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0010] FIG. 1 schematically shows a refrigerator according to an
embodiment of the present invention; and
[0011] FIG. 2 shows a flow diagram for the operation of a automatic
defrost controller according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0012] As shown in FIG. 1, the present embodiment of the invention
provides an automatic defrost controller (ADC) that controls the
operation of a defrost heater in a refrigerator 10 having a cabinet
11. The ADC also controls the operation of a defrosting apparatus
or defrost heater 12, an evaporator fan 14 and a air damper 16
positioned in an air duct 18 located in a divider wall 20
separating a frozen food compartment 22 and a fresh food
compartment 24 of the refrigerator 10. A refrigeration apparatus
25, including a compressor, condenser and evaporator (not
separately shown), is controlled by a freezer control or thermostat
26 to maintain the frozen food compartment 22 at a set temperature.
A fresh food control or thermostat 28 maintains the fresh food
compartment 24 at a set temperature by controlling the opening and
closing of the damper 16 and the operation of the evaporator fan 14
to provide cooling air from the frozen food compartment 22 through
the air duct 18. The defrost heater 12 is located adjacent to a
portion of the refrigeration apparatus, i.e. the evaporator, on
which ice forms in order to remove the ice.
[0013] As shown in FIG. 2, the ADC according to the present
embodiment controls the operation of the defrost heater 12 and the
other components of the refrigerator as follows. The ADC control
flow commences at step S1 when power is provided to the ADC.
[0014] At step S2, if the freezer control 26 indicates that no
cooling is needed in the frozen food compartment 22 (the compressor
is off) control passes to step S3. At step S3, if the ADC
determines from a door sensor or switch 30 that the refrigerator
door 32 has not been opened for a predetermined number of previous
refrigeration cycles or compressor on/off cycles, such as one or
three cycles, then the ADC returns to step S2. Otherwise, if the
door 32 was opened during the last three cycles, then control
passes to step S4.
[0015] At step S4, if the fresh food control 28 is not calling for
cooling then the ADC turns off the evaporator fan 14 at step S5,
closes the damper 16 at step S6 and returns to step S2. Otherwise,
if the fresh food control calls for cooling at step S4, the ADC
opens the damper at step S7, runs the evaporator fan at step S8 and
returns to step S2.
[0016] If, at step S2, the freezer control 26 is calling for
cooling, control passes to step S9. At step S9, if the defrost
relay is not set to defrost, control passes to step S10 where the
ADC pauses for a fan delay time to allow the compressor time to
begin providing cooling air. Next, at step S11, the ADC initiates a
damper cleaning operation, as describe below in more detail, and
then passes to step S12 to run the evaporator fan and then pass to
step S13.
[0017] At step S13, if the freezer control no longer requires
cooling (the compressor has stopped), the evaporator fan is turned
off at step S17. Next at step S18, if the cumulative compressor run
time is greater than or equal to a set defrost interval, X, then
the defrost relay is set to defrost at step S19 and control returns
to step S2. Otherwise, control returns directly to step S2.
[0018] At step S9, if the defrost relay is set to defrost, control
passes to step S20. At step S20, the evaporator fan is turned off,
the damper is closed at step S21, and the defrost heater is
energized at step S22. Next, at step S23, the defrost heater
remains energized until a defrost termination thermostat opens in
response to reaching a set temperature, indicating that the melting
of the frost on the evaporator is complete, at which time control
passes to step S24 and the defrost heater is turned off. ADC
control then returns to step S2.
[0019] As described above and shown in the drawing figure at
reference number 110, the ADC turns off the evaporator fan and
closes the damper during the operation of the defrost heater. This
helps to prevent moisture from collecting on the damper that would
subsequently turn into ice and interfere with the operation of the
damper.
[0020] In order to prevent water that may have accumulated during
defrosting from freezing on or near the damper, the ADC
periodically performs a damper cleaning operation S11 as described
above. During this damper cleaning operation S11, the ADC causes
the damper door to open and close a specified number of times at a
specified frequency. This movement of the damper causes accumulated
water on and near the damper to be removed. As shown in the drawing
figure at reference number 112, the damper cleaning operation S11
is initiated just prior to the operation of the evaporator fan S12.
In the present embodiment, during the damper cleaning operation,
the damper is repeatedly moved to a fully open position and then to
a fully closed position. It is contemplated to be within the scope
of the present invention that the damper may alternatively be moved
to a partially open position and/or a partially closed position
during the damper cleaning cycle. The time between openings and
closings can be set to any appropriate amount, such as 1 or 2
seconds. Alternatively, the damper can be opened and closed in
immediate succession without any delay. The number of open/close
cycles can be set to any appropriate amount, such as one or two or
more. Alternatively, the number of open/close cycles and/or their
timing can be controlled in a closed-loop fashion, such as based on
the length of the prior defrost cycle.
[0021] Further, the ADC monitors a door switch to determine when
the door of the fresh food compartment has been opened. If the
compressor goes through a set number of refrigeration cycles or
"on/off" cycles, without the door being opened, the damper is kept
closed during subsequent compressor "off" cycles. This prevents
migration of cold air from the freezer compartment to the fresh
food compartment when no cooling has been called for by the freezer
control. As shown in the drawing figure at reference number 114,
this is accomplished in the present embodiment by bypassing the
off-cycle damper control routine 116 when the door has not been
opened in the three prior refrigeration cycles S3. It should be
appreciated that the number three has been used as an example, and
that the number of cycles can be set to any appropriate number,
including one, two, four or more. Further, different intervals,
other than refrigeration cycles, to determine when to allow the
damper to be opened when the compressor is off.
[0022] It should be evident that this disclosure is by way of
example and that various changes may be made by adding, modifying
or eliminating details without departing from the fair scope of the
teaching contained in this disclosure. The invention is therefore
not limited to particular details of this disclosure except to the
extent that the following claims are necessarily so limited.
* * * * *